This invention involves a dental prosthesis composition and more particularly is an acrylic polymeric composition capable of polymerization in any desired shape.
The composition of the present invention may be used to prepare full and partial dentures, restoration of carious teeth, as a pit and fissure sealant, as an impression material, as a peripheral seal and fast setting tray material, crown and bridge temporary restoration, a repair composition and other similar applications. Popular and typical polymeric resin compositions for the above applications are those based upon alkyl methacrylate polymers and copolymers and in particular polymers and copolymers of methyl methacrylate. Typical comonomers include butyl methacrylate, ethyl acrylate, and dimethacrylates such as ethylene glycol dimethacrylate, aromatic dimethacrylates such bis-phenol glycidyl methacrylate, urethane diacrylate and other comonomers. A common composition utilizes a portion of difunctional monomer so that cross-linking of the polymerized system results. A typical prosthesis composition includes an acrylic polymeric powder in the form of small beads which is mixed by the dentist or prosthesis preparer with an acrylic monomer composition to form a paste. If the polymerization of the monomer is to take place at elevated temperatures, a peroxide such as benzoyl peroxide, a white powder, is included mixed with the polymer powder. If the composition is to be cured at room temperature, generally described as "cold cure", an accelerator/initiator such as an aromatic tertiary amine is premixed with the monomer such that when the monomer and the polymer are mixed together, the accelerator reduces the half-life of the peroxide and causes polymerization or "cure".
Compositions of dental materials, their preparation, and physical properties are described in great detail in OUTLINE OF DENTAL MATERIALS AND THEIR SELECTION by William J. O'Brien, Ph.D and Gunnar Ryge, D.D.S. and M.S., 1978. W. B. Saunders Company, West Washington Square, Philadelphia, Pa. 19105, Library of Congress ISBN 0-7216-6896-8 and Air Force Manual DENTAL LABORATORY TECHNOLOGY Jan. 22, 1975 supplied by Department of the Air Force, available from Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402, Catalog NO. D 301.7:162-6 and later editions, all incorporated herein by reference.
It is recognized that some of the physical properties of the cold cured acrylic polymer prosthesis compositions are inferior to the physical properties of the oven cured acrylic resins. While it is well recognized that the glass transition temperature, that is the softening temperature, for the "pour-type", cold cured acrylic resins has lower mechanical softening temperatures than the heat cured acrylic resins. In addition, other, more subtle characteristics of the cold cured resin are inferior such as the wetability accuracy, warping, generally due to shrinkage and surface hardness using some tests. Wetability may be described in more technical terms as the contact angle between the liquid and the solid cured resin surface or the surface tension between the liquid surface and the resin surface. The practical advantage of being more hydroscopic is appearance and improved adhesion between the denture and the mouth to keep the plate in place. A number of prosthetic methods and devices have been described in U.S. Patents and all of the techniques and devices may be utilized using the present invention. These patents include U.S. Pat. No. 2,036,715 to H. D. Morgan, U.S. Pat. No. 3,083,459 to M. McMurry et al, U.S. Pat. No. 3,307,260 to Robert H. Allen, U.S. Pat. No. 2,101,431 to Groff, U.S. Pat. No. 3,659,344 to Gavazzi, U.S. Pat. No. 4,017,971 to Hazar and U.S. Pat. No. 4,044,762 to Jacobs all the patents being incorporated herein by reference.
The needs described above and the objects herein below are not satisfied by the compositions or devices of the above patents.